1. Field of the Invention
The invention relates to a fire resistant yarn and to a method of preparing a fire resistant yarn. The invention also relates to a fabric which includes the fire resistant yarn. The invention has particular applicability in the formation of fire resistant fabrics for applications such as upholstery, mattress and pillow ticking, bed spreads, pillow covers, draperies or cubicle curtains, wallcoverings, window treatments, awning covers and baby clothing.
2. Description of the Related Art
It is well known in the textile industry to produce fire resistant fabrics for use as upholstery, mattress ticking, panel fabric and the like, using yarn formed of natural or synthetic fibers, and then treating the fabric with fire retarding chemicals. Conventional fire retarding chemicals often include halogen-based and/or phosphorus-based chemicals. Unfortunately, such treated fabric is heavier than similar types of non-fire retardant fabrics, and further has a limited wear life. Also, this type of fabric typically melts or forms brittle chars which break away when the fabric is burned, and exposes the foam of a composite chair, mattress or panel fabric system. The exposed foam then acts as a fuel source.
It is also known to form fire resistant fabrics of fire resistant, relatively heavy weight yarns in which a low temperature resistant fiber is ring spun around a core of continuous filament fiberglass. However, this type of ring spun yarn has torque imparted thereto during the spinning process and is very lively. Because of the lively nature of the yarn, it is necessary to ply xe2x80x9cSxe2x80x9d and xe2x80x9cZxe2x80x9d ring spun yarns together so that the torque and liveliness in the yarn is balanced in order to satisfactorily weave or knit the yarn into the fabric, without experiencing problems of tangles occurring in the yarn during the knitting or weaving process. This plying of the xe2x80x9cSxe2x80x9d and xe2x80x9cZxe2x80x9d yarns together results in a composite yarn which is so large that it cannot be used in the formation of fine textured, lightweight fabrics. In some instances, the fiberglass filaments in the core protrude through the natural fiber sheath. It is believed that the problem of protruding core fibers is associated with the twist, torque and liveliness being imparted to the fiberglass core during the ring spinning process.
It is the current practice to produce coated upholstery fabrics by weaving or knitting a substrate or scrim of a cotton or cotton and polyester blend yarn. This scrim is then coated with a layered structure of thermoplastic polyvinyl halide composition, such as polyvinyl chloride (PVC). This coated upholstery fabric has very little, if any, fire resistance and no flame barrier properties. In addition to the coating chemical having a limited shelf life, the chemical coatings are disadvantageous in that they pose a safety hazard in case of contact with skin.
To overcome or conspicuously ameliorate the disadvantages of the related art, it is an object of the present invention to provide a novel fire resistant corespun yarn.
It is a further object of the invention to provide a fire resistant fabric which includes the fire resistant corespun yarn in a fire resistant fabric substrate.
It is a further object of the invention to provide a product upholstered with the fire resistant fabric.
The corespun yarn can advantageously be used in forming fine textured or non-textured fire resistant decorative fabrics. Upon exposure to flame and high heat, sheathings of staple fibers surrounding and covering a core become charred and burnt, yet remain in position around the core to create a thermal insulation barrier. The char effectively can block the flow of oxygen and other gases, preventing the fabric from igniting.
In addition, the fabrics woven or knit with the corespun yarn of the present invention can advantageously be dyed and printed with conventional dying and printing materials. These fabrics are particularly suitable for forming fine textured fire resistant flame barrier decorative fabrics for use in upholstery, panel fabrics, mattress and pillow ticking, draperies or cubicle curtains, wallcoverings, window treatments and baby clothing.
In accordance with one aspect of the invention, a fire resistant corespun yarn is provided. The corespun yarn comprises a core of high temperature resistant continuous inorganic filaments, a first sheath of staple fibers surrounding the core, wherein the staple fibers comprise fibers of at least one fire resistant material and a second sheath of staple fibers surrounding the first corespun yarn. Advantageously, a blend of two different fire resistant fibers are provided in the first sheath, one which is effective to char and remain dimensionally stable when exposed to open flame, and a second which releases oxygen depleting gases to extinguish the burning non-flame-resistant fiber in the second sheath.
In accordance with a further aspect of the invention, a fire resistant corespun yarn is provided. The corespun yarn comprises:
a core of high temperature resistant continuous inorganic filaments;
a first sheath of staple fibers surrounding the core, wherein the staple fibers comprise fibers of at least one fire resistant material selected from the group consisting of meta-aramids, para-aramids, fluoropolymers and copolymers, chloropolymers and copolymers, polybenzimidazole, polyimides, polyamideimides, partially oxidized polyacrylonitriles, novoloids, poly (p-phenylene benzobisoxazoles), poly (p-phenylene benzothiazoles), polyphenylene sulfides, flame retardant viscose rayons, polyvinyl chloride homopolymers and copolymers, polyetheretherketones, polyketones, polyetherimides, polylactides, and combinations thereof; and
a second sheath of staple fibers surrounding the first corespun yarn.
Preferably, the continuous inorganic filaments are selected from the group consisting of fiberglasses, carbons, ceramics, quartzes, steels, and combinations thereof, and the core has a structure which includes low temperature resistant synthetic continuous filaments selected from the group consisting of nylons, polyesters and polyolefins such as polyethylene and polypropylene, two-plied with the inorganic filament core.
In accordance with a further aspect of the invention, provided is a fire resistant corespun yarn, comprising:
a two-plied core of continuous inorganic filaments selected from the group consisting of fiberglasses, carbons, ceramics, quartzes, steels and combinations thereof, and low temperature resistant synthetic continuous filaments selected from the group consisting of nylons, polyesters, and polyolefins;
a first sheath of staple fibers surrounding the core, wherein the staple fibers comprise fibers of at least one fire resistant material selected from the group consisting of meta-aramids, para-aramids, fluoropolymers and copolymers thereof, chloropolymers and copolymers thereof, polybenzimidazole, polyimides, polyamideimides, partially oxidized polyacrylonitriles, novoloids, poly (p-phenylene benzobisoxazoles), poly (p-phenylene benzothiazoles), polyphenylene sulfides, flame retardant viscose rayons, polyvinyl chloride homopolymers and copolymers thereof, polyetheretherketones, polyketones, polyetherimides, polylactides, and combinations thereof; and
a second sheath of staple fibers surrounding the first corespun yarn,
wherein the first sheath of staple fibers has a Limiting Oxygen Index of at least 22 as measured by ASTM D 2863.
In accordance with yet another aspect of the invention, a fire resistant fabric is provided. The fabric includes a fire resistant fabric substrate, which includes the fire resistant corespun yarn.
In accordance with yet another aspect of the invention, a product upholstered with the fire resistant fabric is provided. The product can advantageously be free of a fire resistant coating and of a barrier fabric.
Other objects, advantages and aspects of the present invention will become apparent to one of ordinary skill in the art on a review of the specification, drawings and claims appended hereto.